Mr. B from Oregon says:

The house I am currently renting has a Trex deck on the back which is flaking, swelling, and warping. To date, my landlord has shown no inclination to do anything about the situation…are there any health hazards connected with flaking Trex materials? Should I not let my dog play and rest on the deck?

This can be a little tricky to answer, because there are several different composite decking “recipes”, and the manufacturing companies obviously aren’t eager to share their secrets. Whether or not your deck is poisonous depends on the type of plastic used. PVC or vinyl are known to be toxic.

In my research, I didn’t come across any reports of health issues related to the flaking problem. No doubt there’s some dust that could be inhaled, and that could pose a hazard—but the same could be said of all dust from any product, even natural wood. Of course, wood doesn’t tend to disintegrate like composites do…

Along with the flaking, another common complaint with composite decking is mold. Certain types of mold are hazardous to your health, so that’s something to keep in mind.

My bigger concern would be the deck’s structural stability. If the flaking and warping reached a certain point, I’d worry about the deck collapsing. It’s happened before. If you or your dog are on it when the boards start failing, that could certainly cause some health problems in the form of broken bones.